Tag: Cancer

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Treatments

New Eye Cancer Treatment Approved

Targeted Sustained Release Drug DeliveryThe FDA just granted Orphan Drug Designation for a new investigati0nal treatment for retinoblastoma.  Retinoblastoma is an eye cancer causing blindness or death in infants and children.

With timely diagnosis, the survival rate for this childhood cancer is quite high, but the morbidity can be devastating.

What is Retinoblastoma?

Retinoblastoma is a congenital eye cancer involving the retina.  It can occur in one eye, both eyes and/or in the brain.  Undetected, it can be fatal.

The tumor occurs in 1/15,000 – 1/20,000 live births.

When involving one eye, there is usually no family history.  Bilateral (involving both eyes) cases and those involving the brain are hereditary and these patients are also at increased risk for developing other types of malignant tumors.

Treatment of the eye involves enucleation (removal of the eye), chemotherapy, freezing, laser or radiation.

Orphan Drug Designation

This FDA designation is not FDA approval, yet is usually given to drugs with the potential to treat rare diseases affecting fewer than 200,000 people in the United States.

The disease affects so few that it is unlikely a company could ever recoup the normal costs of drug development and introducing it into the market.  Special incentives are given which reduce the financial burden, and a rare disease thus has the hope of finding a treatment.

Intraocular Injection

The treatment involves an old drug, melphalen, and a new technology.  The drug is delivered as a sustained release intraocular injection (similar to Ozurdex) attached to a biocompatible compound which slowly releases the drug into the eye over time.

Icon Bioscience, Inc., has developed Verisome®, a patented technology for releasing drugs into the eye involving a biocompatible polymer with unique chemical properties designed for accurate and prolonged time release.  Several other drugs for treatment of eye disease are under development using the same Verisome® technology.

What Does This Mean?

This is an extreme example of the value of targeted sustained drug release for eye disease.

Intraocular injections have given us great success in treating old diseases.  Ozurdex, Avastin, Lucentis and Eylea are all examples of intraocular injections for various retinal diseases.  The injections have become common place over the past 5 years.

Success is due to targeted delivery of the desired drug to the retina.  Intraocular injections have successfully obviated the “blood brain barrier.”  As a rule, drugs taken by mouth or intravenously simply to not penetrate the eye to any substantial level.

By injecting directly into the eye, the drug surpasses the “blood brain barrier” and much needed drug is delivered, or targeted, to the diseased tissue, the retina.  In addition, as in this case, drug will be released for weeks to months (i.e. sustained release) with a single application.  As a result, new “treatments” emerge.

Perhaps a “cure” for this horrible eye cancer develops simply by changing the route of administration, sustained release and an incentive plan from the FDA.

Randy

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia

 

Categories
Macular Degeneration Treatments

FDA Upholds Denial of Avastin

Avastin is no longer FDA approved for breast cancer.  This decision was upheld at a hearing last week.  Eye patients, however, need not worry.

The Food and Drug Administration had removed its approval for Avastin for the treatment of breast cancer last December.  A hearing last week (June, 2011) allowed Genentech and the drugs’ supporters, to voice their concerns about the removal of the drug.

  • While the FDA has removed its approval for one type of cancer, the drug is not being removed from the market.

The FDA argues that bevacizumab (generic name) is not effective in treating breast cancer patients and, so,  reversed its original decision.  The counter argument claims that Avastin is effective, though in a minority of patients.

This anti-VEGF drug has become effective treatment for wet macular degeneration.  Avastin, used for the treatment of a variety of cancers, has become the standard of care and is used my most retinal specialists for their patients.

Avastin Not Effective for Breast Cancer

The initial data indicated that bevacizumab, when given along with another drug, stymied the progression of the disease for 5-6 months compared to the other drug alone.  Avastin was given quick approval for breast cancer.

Since then, re-investigation could not duplicate the results, yet the incidence of GI bleeding complications were notable.  There was no evidence showing improved lifespan either.

The FDA upheld the decision.

What Does This Mean?

Removing an FDA approval only means that insurance companies are likely not to reimburse doctors and hospitals for the treatment.  While treatment can theoretically still be performed, it would require that patients pay for it out-of-pocket.  Thus, it is cost prohibitive in most cases.

Regardless of the FDA hearing, eye patients do not need to worry.  Though the drug may no longer be available for patients with breast cancer, the drug will still be on the market for other treatments.

We should be able to continue using it as a first line treatment for wet macular degeneration.  Avastin may have lost its FDA approval for the treatment of breast cancer, but this is different than a drug being removed from the market.

(By the way, I have wondered why the FDA could not have compromised, in that, as long as existing patients accept the risks, treatment could continue.  Why not remove the FDA approval from this point forward?)

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Categories
Macular Degeneration Treatments

Radiation and Lucentis Combined to Treat Macular Degeneration

External beam radiation and Lucentis may be combined to treat wet macular degeneration.    The results showed the treatment may be very safe and, when combined with anti-VEGF injections such as Lucentis, may decrease the need for frequently repeated injections.

Neovascularization, the growth of abnormal blood vessels, underneath the macular defines “wet macular degeneration.”

Radiation Kills Cells

Radiation treatments have been used in and around the eye to treat tumors.  Radiation, in this case, halts the replication of cells.  In the case of tumors, the lesions can no longer grow.  So too, with neovascularization, new growth is inhibited.  This is not the first study that has investigated the use of radiation for wet macular degeneration, but this is one of first trials combining external beam radiation with Lucentis.

Side Effects of Radiation to the Eye

Radiation can be toxic to the eye.  It can cause cataracts, damage to the optic nerve and retina.  It may also damage the lacrimal (produces tears to the eye) system and cause dry eye.

The investigators were able to dose and administer the radiation safely, seemingly able to avoid the usual complications of external beam radiation.

Treatment Required Fewer Injections of Lucentis

The gold standard for treating wet macular degeneration is now injections with either Lucentis or Avastin.  The injections, however, need to be repeated as often as monthly.  While highly successful, the need for repeated treatment requires a lot of trips to the office and can be expensive.

The study combined the use of the popular anti-VEGF agent, Lucentis (ranibizumab).  The design of the trial required 2 initial injections during the first month of treatment.

52% of patients did not require additional injections for the 12 month study period (they only had 2!).

Also noteworthy, most patients stabilized and actually improved their vision.

What Does This Mean? This is not an approved treatment.  It is in no way a true “study,” but this small trial still has some merits.  It provides us with a small amount of evidence that alternative treatments using radiation may be useful.

First, recall that anti-VEGF injections, such as Lucentis or Avastin, now standard therapy for wet macular degeneration, were developed for chemotherapy against several types of cancers.  The discovery that this improved patients with macular degeneration was coincidental.

For instance, patients receiving chemotherapy for colon cancer started noting improvement in their vision.  Evidently, these patients had both cancer and wet macular degeneration.

External beam radiation has long been used for many types of cancer treatments.

In both cases, agents that halt rapidly dividing (i.e. growing) tissues should be effective in both the cancer treatment and the eye disease.  The radiation stymies cell replication and the Lucentis (anti-VEGF) inhibits grow of new blood vessels.  In the case of cancer, a tumor can not enlarge without blood supply.

So, it makes sense that this may work.

Lastly, this really underscores the need for treatments that do not need to be repeated so frequently, such is the case with Lucentis and Avastin.  Right now, most doctors inject as frequently as every 4-6 weeks!  Drug delivery systems designed to release drug over an extended period may aid this as well.

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